Add exe packaging and install.bat

- esbuild bundle + @yao-pkg/pkg for standalone Windows exe
- install.bat copies to %LOCALAPPDATA%\kisync and adds to user PATH
- npm run package to build release/kisync.exe

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

package.json

@@ -8,6 +8,8 @@
   },
   "scripts": {
     "build": "tsc",
+    "bundle": "esbuild dist/index.js --bundle --platform=node --target=node18 --outfile=bundle/kisync.js",
+    "package": "npm run build && npm run bundle && pkg bundle/kisync.js --targets node18-win-x64 --output release/kisync.exe",
     "dev": "ts-node src/index.ts",
     "start": "node dist/index.js"
   },
@@ -19,6 +21,8 @@
   "devDependencies": {
     "@types/node": "^20.10.0",
     "@types/node-fetch": "^2.6.9",
+    "@yao-pkg/pkg": "^5.11.0",
+    "esbuild": "^0.20.0",
     "typescript": "^5.3.2",
     "ts-node": "^10.9.2"
   }